Direct marketing is one of the most controversial methods of advertising channels, especially when the approaches included are unsolicited.
Some common examples include TV and Telephonic commercials and the direct mail. Electronic spam and telemarketing also push the limits of ethical standards and legality in a strong manner.
Example − Shills and astroturfers are the best examples of ways for delivering a marketing message under the guise of independent product reviews and endorsements, or creating supposedly independent watchdog or review organizations. Fake reviews can be published on Amazon. Shills are primarily for message-delivery, but they can also be used to drive up prices in auctions, such as EBay auctions.